AbstractThe formulation and control of margarine and margarine oils is based primarily on an understanding of the relationships between specific physical measurements and the compositions of the oils blends and their components, and secondarily, on an appreciation of processing effects, Desirable solids‐to‐liquid ratios are achieved by blending and hydrogenation control. Oils are chosen for their peculiar crystal habit resulting from conditions of processing both as oils, for components, and as a finished margarine product. This presentation identifies the underlying principles directly responsible for (a) proper formulation and control to achieve desirable finished product characteristics, (b) for choosing proper testing methods and (c) for developing adequate in‐process controls.